A self-activated silicate phosphor of Na5YZrSi6O18

• Na5YZrSi6O18 was firstly developed to be a new bluish green-emitting silicate.
• Na5YZrSi6O18 presents unusual properties: efficient excitation and longer emission wavelength.
• Na5YZrSi6O18 shows long-lasting phosphorescence with duration time above 3 h.

A new self-activated silicate phosphor of Na5YZrSi6O18 was prepared by a solid-state reaction method. The phase formation was confirmed by X-ray powder diffraction measurement. The photoluminescence excitation and emission spectra, X-ray-excited luminescence, decay curves, quantum efficiencies and the color coordinates were investigated. It can be efficiently excited by UV light and X-ray and presents unusual green emission (centered at 475 nm) from Zr4+ to O2− charge transfer transition. Meanwhile, the phosphor shows long-lasting phosphorescence with duration time above 3 h after the removal of excitation. The afterglow curves and thermo-luminescence were measured for pure and rare earth ions (RE = Yb, Er, Ho, Dy, Tb, Sm, Nd) doped Na5YZrSi6O18. The possible defects and the mechanism of long-lasting phosphorescence were suggested on the base of the strong disorder of the multiply cation sites in the lattices.

Self-activated Na5YZrSi6O18 shows a bright green luminescence. It presents obvious LLP afterglow with duration time >3 h after the removal of excitation. The substitution of Y3+ by rare earth ions except Yb3+ cannot prolong the afterglow. It is proposed that the disorder in the lattices can result in different trap centers attributing to the long last phosphorescence.Figure optionsDownload as PowerPoint slide